ISX 12 code 4726 and 0559

[Rawze]

(02-06-2025 )FarmLife Wrote:  Removed the high pressure fuel pump head. Put shop air to the port on the front of the pump to extend the plungers. The plungers would not move. Was able to take off the springs and pull the plungers up by hand. When you push the plungers down they come back up like they should. Since the plungers would not extend with shop air does this mean the check valves in the top of the head are stuck?

there is more to testing the plungers than just pushing on htem... here is the way to test them...
ref: http://rawze.com/forums/showthread.php?t...8#pid60008

if the ecm has delete programming in it...
A)> make a copy and send it to me for a review. Fo all anyone knows, some yahoo could have jacked with the fuel pressures, cauysing damage to the fuel system of pump over time... damage ti the engine, turbo.. who knows.
info: http://rawze.com/forums/showthread.php?t...5#pid72945

b)> after making a successful back copy of the programming (using Calterm), put latest factory programming in it and see if it has the same issues.